Polls show Democrats are likely to win control of the House, with Republicans likely to retain their majority in the Senate.
Here is what to expect, based on interviews with more than a half a dozen congressional aides:
* The majority party in the House or Senate receives more money and staff for investigations than the minority party. Control of key House panels, such as the committee on oversight and government reform, the judiciary committee, the tax-writing ways and means committee and the permanent select committee on intelligence, is expected to shift to top Democrats.
* Democratic House leaders and prospective committee chairs already have been discussing the scope and sequencing of investigations they will launch if they win control.
They will move swiftly to energise an oversight process they believe has stalled.
Representative Adam Schiff, the top Democrat on the House intelligence panel, wrote in a recent Washington Post op-ed that Democrats must “restore Congress as an equal branch and check the ambition of an imperial and erratic president”.
* Democratic leaders have made clear they will not pursue Trump’s impeachment - at least until the outcome of Special Counsel Robert Mueller’s investigation of Russian meddling in the 2016 US elections and possible Trump campaign collusion with Moscow.
Trump has refused to release his tax returns, bucking the custom of recent US presidents. The ways and means committee would use its authority to request Trump’s tax returns from Treasury Secretary Steven Mnuchin.
The judiciary and intelligence committees could then use the returns to dig into whether Trump got anything of value from foreigners or had business ties to Russia.
* The House committee on oversight and government reform has the broadest oversight jurisdiction and can examine any federal agency, person or company. Representative Elijah Cummings, currently the panel’s top Democrat, is expected to chair the committee. Cummings said he would take a “two-lane” approach, examining Trump’s businesses and potential conflicts of interests, while also probing “day-to-day” issues such as prescription drug pricing, voter suppression and questions about citizenship added to the 2020 US Census.
During Trump’s presidency, oversight Democrats sought 64 subpoenas that Republican committee members denied, which offers an indication of their intentions.
* Democrats will aim for some bipartisan co-operation in conducting their investigations, lest their push seems too overtly political ahead of the 2020 presidential election.